Congress is coming back to town this week to finish action if it can on two big bills that President Carter wants passed - energy and Social Security - and to start action a third:

The President's plan for restructuring the welfare system.

A special House welfare subcommittee is scheduled to begin making decisions Tuesday on the controversial welfare bill. Its chairman, Rep. James C. Corman (D-Calif.), says perhaps optimistically that it can complete its work by Christmas.

The bill the subcommittee approves will then be sent to the three standing committes of the House from whom the subcommittee members have been drawn: Ways and Means, Agriculture, and Education and Labor, each of which has jurisdiction over some part of existing "welfare" law.

According to plan, these standing committees will mark up their parts of the legislation next year and send it all to the floor as one bill. It it survives there, it will go to the Senate. But the welfare plan's chances of even House passage are uncertain: key House members have already announced that they oppose several of its most important provisions.

Rep. Thomas S. Foley (D-Wash.) for example, a member of the Corman subcommittee, is strongly opposed to Carter's plan to eliminate food stamps, and put the $5.6 billion that step would save into a new and expanded system of welfare or straight cash assistance.

Foley is also chairman of the Agriculture Committee which last summer overhauled the program that helps 17.1 million Americans buy food, and extended it for four more years. The changes his committee made don't even take effect until next summer.

Rep. Al Ullman (D-Ore.), another subcommittee member, said when congressional hearings began back in mid-September that the Carter plan is "totally unworkable."

Ullman's view is important because he also chairs the Ways and Means Committee.

Ullman is concerned about the precedent of a guaranteed annual income, especially for the new groups that Carter proposes to make eligible: childless couples, some families with an unemployed father in the home, single persons who are not aged, blind or disabled, and families of the "working poor" who have very low wage jobs.

"Thirty-two million Americans will be getting checks from the government, and half that will get them for the first time," he said, "not on a real basis of the kind of jobs they have put on the number of people in their family."

Rep. Augustus F. Hawkins (D-Calif.), co-author with Sen. Hubbert H. Humphrey (D-Minn.) of the full employment bill that Carter recently endorsed, is the acknowledged expert on the part of the plan expected to create 1.4 million public service minimum wage jobs for welfare recipients who can't find any other kind of work.

A spokeman said Hawkins has reservation about that, including the assumption built into Carter's plan that only 1.4 million such jobs will be needed because unemployment will be below 5.6 per cent, and the plan to attach them to minimum wage salaries.

In some ways, the problems the Carter plan faces in the welfare subcommittee are similar to those that killed the last major administration attempt to overhaul the welfare system.

That was President Nixon's Family Assistance Plan, introduced in 1971 as the top priority of his administration.

It was similar to Carter's plan in that it set up a guaranteed annual income and included work requirements. But its different components faced so much opposition from all parts of the political spectrum that a sharply divided Senate, unable to agree on how to change it, killed the whole thing in 1972.

Corman seemed optimistic earlier this month that his subcommittee would approve the key elements of the $30.7 billion plan by Dec. 22. Other key subcommittee members weren't so sure, however.

There appears to be considerate interest at this early stage in a more gradual approach to reform suggested by Richard P. Nathah, a Brookings Institution researcher who worked on Nixon's Family Assistance Plan.

"In my view the welfare mess has been overstated," Nathan told the subcommittee. ". . . Our social programs are much more logical than many people realize. They have grown tremendously. It is hard to be poor in this country now."

Nathan suggested a less ambitious overhaul than Carter asked for, an "incremental approach to welfare reform would be easier for the Congress to work with and better for the nation."

An aide to Foley, who asked not to be identified, said, "I think in a broad sense he agrees with Nathan . . . that a comprehensive approach without a clear idea of what some of the ramifications of the program could be is just nothing we should be jumping into. Maybe the best idea would be to make some changes . . . rather than to try to do any full overhaul . . ."

Rep. Barber B. Conable Jr. (R-N.Y.) said he is ". . . kind of concerned about what appears to be a negative view on the part of the subcommittee about the whole welfare reform package."

Conable said the subcommittee can report out a bill by Dec. 22 "if they can give it their undivided attention." But he noted that the conference on the energy program is still going on and added, "for something on which the political payoff is likely to be nothing but controversy, they're not as likely to make time."

The welfare program by now is a large government institution, he said, adding that "large government institutions frequently are more easily adjusted incrementally."

Ullman, too, is reported to be working out a simplified version of the Carter proposals.

"At this point there isn't a hell of a lot of consensus on the welfare bill as Carter has proposed it," said one key staff member who asked not to be identified.

"The geometry of the committee as it stands is difficult. Corman, who is fifth ranking . . . really has been put over three standing chairmen of three large committees, all of whom are very conscious of their own turf . . ."

A Democratic of the subcommittee, who also asked not to be identified, voiced similar feelings.